[7] In addition to his native country he worked as a counsel or representative for various states including Equatorial Guinea, Germany, Honduras, Hungary, Italy, Mali, Mexico, Portugal, Spain and Tunisia before the International Court of Justice in The Hague.
He acted inter alia as consultant to the OECD, the United Nations Environment Programme, the Bureau International des Expositions, UNESCO and Eutelsat.
He is also listed as notable Global-wide Arbitrator in the field of Public International Law by Chambers and Partners.
In March 2003, Dupuy was one of the "eminent academic lawyers" who wrote opposing the 2003 invasion of Iraq.
[9] Professor Pierre-Marie Dupuy is fluent in French, English, Spanish, Italian and German.